A disk drive comprises a disk which may contain defects from a manufacture of the disk or through wear and tear over time. Such defects may make portions of the disk unusable and are mapped in a defect log to prevent accidental storage of data in the defect. The defect may be a physical defect in the disk. In such a case, areas near the physical defect may also be considered to be a defect as a precautionary measure. The areas near the physical defect may therefore be margined and also be identified as a defect in the defect log.
To identify the defects, the defect log contains defect records. Each of the defect records contains record fields. In some situations such as during failure analysis, it may be beneficial to search for a specific defect record in the defect log, or many defect records which match certain search criteria. To search the defect records in the defect log, selected record fields in each of the defect records are searched to determine when the desired defect records have been found.
However, the defect records are read on a word by word basis and the record fields may span multiple words. Thus, multiple words of the defect record may need to be read, when the selected record fields span multiple words. Furthermore, multiple words may need to be read, even when only a single record field need be utilized, if the single record field spans multiple words. This can increase, for example, an amount of time needed to search the defect records in the defect log.
Furthermore, the record fields in the defect records may contain too little, or too much information for relevant failure analysis of the disk drive. Thus, the bits in the defect record may not be efficiently used. In such a case, each of the defect records in the defect log may utilize a large amount of space in the defect log, resulting in less defect records being stored in the defect log.